Evolution of the microstructure and lubrication mechanism of AgTaO3 films at high temperatures: A MD simulation study

Ternary oxides are widely used as solid lubricants in aerospace industry due to their ability to reduce friction at high temperatures. Here, we studied sliding friction behavior of films of the ternary oxide silver tantalate (AgTaO3) at different temperatures by molecular dynamics simulations (MD). The results indicate that the friction on the AgTaO3 film decreased with increasing the temperature, and at a temperature of 750 °C the frictional force decreased to 70% of its value at room temperature. The excellent lubrication property of the investigated AgTaO3 film is mainly attributed to the fact that the number of silver clusters formed on the friction surface increases with increasing the temperature, which is related to the thermal and shear-induced breaking of Ag-O bonds. The effects of normal load and shear speed on the generation of silver clusters are also discussed. The Pearson correlation analysis showed that the normal load plays a key role in the observed low friction on AgTaO3 film.